In the prior art there are many arrangements wherein a telecommunications network controls groups of telecommunications terminals in order to provide the members of the group with the kinds of features that are otherwise provided from private branch exchanges and/or key telephone systems. For example, commonly available Centrex® systems allows the individual callers of the group to reach each other by dialing a much smaller number of digits (typically 3–6 digits) while still allowing the members of the group to reach the outside world by dialing an access code (typically “9”) followed by a regular (POTS—plain old telephone service) telephone number. Virtual Centrex service can also be provided by having an intelligent network with a service control point (SCP) having a database to supply the data necessary for providing the individual telephone stations with services including those of a Centrex system. Intelligent network systems frequently provide outgoing or incoming call screening, i.e., selective blocking of calls based on the calling or called number. Such systems can also be used for serving mobile stations.
A problem of the prior art is that in order to make any kind of change such as removing a call restriction from a particular station it is necessary to go through an administrative procedure in the common carrier serving the members of the group. Changes therefore can typically be made only in a matter of days. This is undesirable, for example, to modify a restriction on the number of minutes of use allowed to a particular group member.